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Topic: Open joist soundproofing project (Read 1627 times)

We record video and audio for online classes at our office. Our 1200 square foot office resides on the second floor in a building that was built around 1860. The building is made of wood support columns, brick and mortar. The ceilings are exposed, unfinished joists, and the floors are finished hardwood pine. There is no “soundproofing” or sound mitigation system at our office.

Directly overhead, our new 3rd floor neighbor is an audio and video production equipment rental and service company which uses an 700 square foot office and located over the east side of our office. The other neighbor uses 983 square feet over the remaining west half of our office. Both neighbors generate unpredictable impact and airborne noise peaking at about 85 dB from as early as 7 am until 1 am, leaving us a window of 5 hours of viably silent recording time.

SOLUTION SCENARIOS:

Scenario A calls for removing the existing floor and installing a new multi-layer, vibration-absorbing isolated floor. It is the best noise abatement solution because it stops impact noise at its origin point (the floor) and cuts impact and airborne noise by at least 40 dB, and prevents impact sound from being transmitted into the walls and structural beams below. Any remaining noise issues can be mitigated with minimal sound abatement materials at the ceiling level below the floor. This scenario is not being considered because it would destroy the existing beautiful hardwood floor which is at least 100 years old.

Scenario B calls for installing a new multi-layer vibration-absorbing isolated floor over the existing floor. This is an excellent solution as well because it works similarly to Scenario A. It is strongly recommended that any loose planks on existing floor be tightened and any large gaps be filled with acoustic sealant. Because this floor isn’t screwed or nailed down into the existing floor, it could be removed if needed without harming the existing hardwood floor. The new floor would increase floor height by approximately 2” thus Scenario B will require building a gentle floor ramp in or outside of their office that transitions from the existing hardwood floor to the new floor. This scenario is not being considered because it involves temporarily relocating the existing tenants in Suite 335 and 328 while work is performed and building a ramp into the existing floor would be difficult.

Scenario C calls for mitigating the overhead impact and acoustic noise at the ceiling level by installing thin shims under squeaky floorboards and joists, installing multiple layers of acoustic dampening material between the joists and north-facing walls, then installing a 3mm-thick mass-loaded material across the entire ceiling and walls. A new floating ceiling with echo reduction panels will be installed, as well as echo reduction panels. This method is estimated to cut down noise by 20 to 35 dB. It must be pointed out that because the overhead floor is not mechanically separated from the building as in Scenario A or B, impact sound can still travel downstairs through any wall or main support columns which is why the north-facing walls need to be “soundproofed” as well.

The question that is posed here is what is the best acoustical dampening material to use? Should we use spray foam? Safe'n'Sound? Quiet Batt? Of course, cost and space is a factor so we are looking to use the most affordable and thinnest materials possible with the maximum amount of acoustical dampening qualities.